1. Technical Field
The present invention relates to a toner cartridge, and more particularly, to an image forming apparatus using a charging method in which electric discharge is used as a principle.
2. Related Art
Conventionally, to simplify device configuration and to avoid toner contamination of a toner cartridge mounting section, the following toner cartridges have been widely used.
That is, the toner cartridge includes two containing cases, i.e., a cylindrical inner containing case and an outer containing case which rotatably holds the inner containing case. In a state where the two containing cases are inserted into and fixed to an apparatus, an inner containing case is rotationally operated so that a toner supply opening can be opened and closed.
In the cartridge having the above-described configuration, however, it is required to increase the diameter of the cylindrical portion to increase the maximum toner amount to be filled. Especially in the case of a full color image forming apparatus which requires cartridges of four colors (YMCK), increasing a diameter of the cylindrical portion seriously influence on apparatus size.